In conventional rubber products, such as automobile tires, conveyor belts, and hoses, which are required to have high strength and high durability, the rubber is reinforced with metal materials such as steel cords. As a method for manufacturing such composites of rubber with metal materials, a method called direct vulcanization adhesion method has been known in which vulcanization of rubber and adhesive bonding between a metal material and the rubber are simultaneously performed.
For example, in manufacturing an automobile tire, kneaded rubber is formed by adding carbon black, a vulcanizing agent, and the like to masticated rubber, and then mixing them with each other. Thereafter, a vulcanization treatment is performed on the kneaded rubber. In the vulcanization treatment, a vulcanization accelerator is used to accelerate the rate of the vulcanization reaction.
When, however, the effect of accelerating the vulcanization reaction is too high, there is a concern that an initial-stage vulcanization reaction may proceed during storage before the vulcanization treatment or during operations before the vulcanization treatment (the proceeding of the reaction being called scorch). For this reason, the rate of the vulcanization reaction is adjusted by using a vulcanization retarder having an effect of preventing the scorch (called a retarding property) in combination with the vulcanization accelerator.
In the case of the direct vulcanization adhesion method, for example, a sulfenamide-based vulcanization accelerator such as N,N-dicyclohexyl-2-benzothiazolylsulfenamide (hereinafter referred to as DCBS) represented by the following formula (1) is used.

Examples of known sulfenamide-based vulcanization accelerators other than DCBS include bis(sulfenamide) (see, for example, Patent Document 1), and a benzothiazolylsulfenamide-based vulcanization accelerator (for example, Patent Document 2) for which an amine derived from a natural fat and oil is used as a raw material.